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The pregnant "waddle": an evaluation of torso kinematics in pregnancy.

McCrory JL; Chambers AJ; Daftary A; Redfern MS

J Biomech 2014 Sep; 47(12):2964-2968

https://doi.org/10.1016/j.jbiomech.2014.07.009

20046978

Although pregnant women are anecdotally said to "waddle" during gait, researchers have not quantified the kinematics of these gait alterations. The purpose of this study was to examine the effects of pregnancy on thoracic and pelvic kinematics during gait. METHODS: Data were collected on 29 pregnant subjects in the mid-second and third trimesters and on 40 control women. Three-dimensional kinematic data were collected on subjects walking at their freely-chosen speed. Right foot heel-strike (RHS) and left foot toe-off (LTO) were determined from force plate data. Thoracic and pelvic angles at RHS, step width, mediolateral translation of the C7 and L4 vertebrae, and the ranges of motion (ROMs) of the thorax and pelvis over the gait stride were determined. A series of MANCOVAs were performed with trimester (second, third, and control) as the independent variable and velocity as the covariate (a=0.05). Post-hoc analyses were performed when appropriate. RESULTS: Increased lateral translation of the C7 and L4 vertebrae (third trimester>second trimester>control, p<0.05) was noted, accompanied by an increased step width in the third trimester (p=0.03). At heel strike, pregnant women had greater thoracic extension (third trimester>second trimester>control, p<0.05) and greater anterior pelvic tilt (third trimester>control; p<0.05). Sagittal plane thoracic ROM was less in the third trimester compared to controls (p<0.01). CONCLUSIONS: Pregnant women demonstrated a lateral shifting of the body during gait, which accompanied a greater step width. The increased thoracic extension and anterior pelvic tilt, along with decreased sagittal plane ROM are likely adaptations to increased abdominal size.

Humans; Women; Pregnancy; Posture; Physiology; Physiological-effects; Physiological-function; Body-weight; Body-mechanics; Body-burden; Thorax; Age-groups; Musculoskeletal-system; Biomechanics; Author Keywords: Gait; Kinematics; Pregnancy; Range of motion; Trimester; Walking

Jean L. McCrory, Division of Exercise Physiology, Department of Human Performance and Applied Exercise Science, 8315 HSC-South, PO Box 9227 Morgantown, WV 26506-9227

JBMCB5

20140922

Journal Article

jlmccrory@hsc.wvu.edu

Grant

2014

Grant-Number-K01-OH-008548

12

0021-9290

Journal of Biomechanics

WV; PA

University of Pittsburgh